Dewaxing apparatus



Aug. 13, l940- w. a. CHENAULT DEWAXING APPARATUS Filed Dec. 3, 1937ATTORNEYS Patented Aug. 13, 1940 UNITED STATES DEWAXIN G APPARATUSWilliam Blewett Chenault, Wellsville, N. Y., as-

signor to Sinclair Refining Company, New York, N. Y., a corporation ofMaine 3 Application December 3, 1937, Serial No. 177,870

2 Claims.

This invention relates to apparatus for use in dewaxing hydrocarbon oilsand, more particularly, to apparatus for use in the centrifugal dewaxingof hydrocarbon oils. In its more specific 5 aspect, my invention relatesto a sight-glass for use in conjunction with centrifugal dewaxingmachines whereby a sample of dewaxed oil discharged from said machinesmay be drawn olf, inspected while stationary, and then returned to themain body of dewaxed oil.

The centrifugal dewaxing machines in general use today for thecontinuous dewaxing of hydrocarbon oils are provided with a rundown linethrough which the substantially wax free oil dissolved in a suitablediluent is discharged from the centrifuge. This rundown line is furtherprovided with a look-box which comprises an enlarged portion of the linehaving a glass face so that an operator may observe the flow of wax freeoil through the rundown line. Due to the fact that the wax free oil isdischarged from the centrifuge at a low temperature, the look-boxsoon'frosts over to such an extent that it is dimcult to see the oilflowing through the rundown line. Moreover, it is necessary that the waxfree oil be unhindered in its flow through the rundown line, and forthis reason the oil flowing through the look-box is in continual motion.

In order to observe the physical condition of the wax free oildischarged from the centrifugeit has become the general practice to takea sample of the wax free oil and examine the sample to ascertainwhetheror not the discharged oil contains particles of suspended wax.Heretofore these samples of the wax free 011 have been obtained, forexample, by removing a plug from a hole in the rundown line, insertinginto this hole in the rundown line a nipple with a cut-away section, andwithdrawing a sample of the wax free 40 oil into an improvised look-boxhaving glass sides mounted in a wooden frame. This method of taking asample of the oil has been characterized 'by a considerable amount ofspillage on the floor around the centrifuge. When naphtha or othersimilarly highly inflammable diluent is used as the dewaxing agent inthe centrifuge, this spillage has presented a serious fire hazard.Furthermore, it has been necessary heretofore to remove from the rundownline at least about five or six times the volume of the improvisedlook-glass in order that the sample finally obtained be substantially atthe temperature of the oil as it is discharged from the centrifuge.Inasmuch as this wax free oil withdrawn for sampling must be discarded,a substantial waste has been the natural concomitant of the samplingoperation. When it is considered that samples must be withdrawn atfrequent intervals from as many as forty or more machines in a singleplant, the extent of this waste will be readily apparent. More- 5 over,due to the length of time required to obtain and to inspect this sample,serious difliculty has been encountered due to the increase intemperature of the sample of oil. Any wax which may have beencrystallized and which may have been 10 visible in the oil as it leavesthe centrifuge dissolves in the diluent with the rise in temperaturethereof. Still another difficulty has been encountered in obtaining sucha sample of wax free oil in that air and moisture drawn into the 15sample from the atmosphere give a cloudy appearance to the sample withresulting difiiculty in obtaining a satisfactory inspection of thesample.

I have discovered that a truly representative sample of the wax free oilmay be obtained, that 20 spillage may be avoided, and that the waste oflarge volumes of oil heretofore necessarily removed from the rundownline and subsequently discarded can be eliminated by means of asightglass installed in the rundown line of the cen- 25 trifugalmachine. This sight-glass comprises means for withdrawing at least aportion of the substantially wax free oil from the rundown line of thecentrifugal machine, means for visibly confining the oil withdrawn fromthe rundown line, 30 and means for returning said portion of oil to therundown line. Additional means are provided with advantage for bringingthis portion of oil to rest within the transparent tube whereby asatisfactory inspection of the portion of oil may be 5 made while theoil is stationary.

The apparatus of my-invention will be more fully understood by aconsideration of the accompanying drawing in which:

Figure 1 comprises a perspective view of a portion of a typicalcentrifugal machine showing the rundown line-with the sight-glass of myinvention;

Figure 2 is an enlarged view of the sight-glass of my invention showingits installation in the 45 rundown line; and 1 Figure 3 is a sectionalview taken along line 3-3 of Figure 2 showing the details of the upperconnection for the sight-glass with the rundown line.

As shown in Figures 1 and 2, the sight-glass of 50 my inventioncomprises a glass tube 5 suitably connected by means of a packing gland6 with a nipple l. A portion of one end 8 of this nipple is cut away asshown iniFlgures 2 and 3 and is preferably threaded into the rundownline so as to maintain a sealed connection. The cutaway portion of thenipple inserted into the rundown line with the cutaway portion facingupwardly acts as a trough to carry off at least a portion of the waxfree oil flowing through the rundown line. The lower end of the glasstube is connected by means of a packing gland Ill with a suitable valveH which, in turn, is connected to pipe 12 communicating with the rundownline. This pipe is suitably connected with the rundown line by means ofa bushing l3, or the like, at a point in the rundown line preferablybelow the look-box M. Thus, it will be seen that the sight glass of myinvention comprises a transparent tube suitably connected at either endto different points in the rundown line of the centrifugal machinewhereby at least a portion of the substantially wax free oil flowingthrough the rundown line may be withdrawn from the line, inspected whilestationary, and then returned to the line.

In using the sight-glass of my invention to inspect a sample of oil thevalve II is opened and the oil caught in the cutaway portion 8 of nipple1 runs through glass tube 5, through valve II and pipe l2 back into therundown line. After the oil has run through the sight-glass for asuiiicient length of time so that the temperature of. the oil in thesight-glass is substantially that of the oil as it is discharged fromthe centrifuge into the rundown line, valve II is closed and the oil inthe sight-glass brought to rest. Any frost which may have formed on theoutside of the glass tube made be easily removed by wiping it with acloth moistened with alcohol, or some equivalent means. In this way, theoperator may readily inspect the oil to determine whether or not the oilcontains suspended particles of wax which. if present in the oil, shouldbe removed by subsequent treatment thereof.

It will be seen, therefore, that the sight-glass of my inventioncomprises an inexpensive device which may be readily attached to therundown line of a centrifugal machine. Inasmuch as this sight-glass isconnected at all times in a closed circuit with the rundown line, thereis avoided the fire hazard encountered heretofore by the spillage of oiland solvent around the machine. Furthermore, the temperature of the oilin the sight-glass is substantially that of the oil as it leaves thecentrifuge and comprises a truly representative sample of thesubstantially wax free oil. Inasmuch as the oil which passes through thesight-glass is returned to the rundown line, there is eliminated thesubstantial waste which heretofore has been characteristic of thesampling operation.

I claim:

1. In a centrifugal machine for removing precipitated wax fromhydrocarbon oils, the centrifugal machine being provided with a rundownline for discharging substantially wax free oil from the machine, theimprovement which comprises means extending within the rundown line forwithdrawing at least a portion of the oil from the rundown line, atransparent tube for visibly confining the oil withdrawn from therundown line, means for returning said portion of oil to the rundownline, and means disposed intermediate the transparent tube and saidreturning means for bringing said portion of oil to rest within thetransparent tube.

2. In a centrifugal machine for removing precipitated wax fromhydrocarbon oils, the centrifugal machine being provided with a rundownline for discharging substantially wax free 011 from the machine, theimprovement which comprises a trough extending within the rundown linefor withdrawing at least a portion of the oil from the rundown line, atransparent tube communicating with the trough for visibly confining theoil withdrawn from the rundown line, means for returning said portion ofoil to the rundown line, and means disposed intermediate the transparenttube and said returning means for bringing said portion of oil to restwithin the transparent tube.

